This invention relates to the noise jamming of threat radars, and more particularly to a synchronized pseudo random jammer with false target scintillation.
A military radar operating in a hostile environment may be subjected to deliberate interference, or jamming, which appears as extraneous responses on the radar display. The extraneous responses may be few in number and resemble realtargets, or there may be a large number which fill a significant portion of the display. The purpose of jamming a radar is to create deliberate interference and to degrade its usefulness as part of a weapon system. The various techniques that electronically interfere with radar performance are called electronic countermeasures (ECM). Military radars must be designed not only to perform well in a peacetime environment but to fulfill their mission in time of hostilities in spite of ECM.
Electronic countermeasures can be divided into two classes, depending upon whether they are intended primarily for confusion or for deception. The purpose of a confusion countermeasure is to mask or hide real targets by cluttering the radar display. Its effects are similar to ground or sea clutter except that truly effective confusion ECM usually covers more area on the radar display than does clutter. In fact, effective jamming should completely obliterate the radar screen. An example of a confusion countermeasure is a high power CW transmission modulated by broadband noise.
The purpose of deception ECM is to present to the radar false signals which appear as though they were echoes from real targets. If a sufficiently large number of false targets were to appear on the radar display, the operator might not be able to process them all. Some real targets might be lost, or else the radar operator might direct a weapon to a nonexistent target. An example of a deception countermeasure is the repeater jammer, which plays back to the radar a replica of its own radar signal, but delayed in time, so that it appears displaced in range and/or angle from the true target.
The present invention creates confusion by creating a scintillation-like effect on false targets which makes it extremely difficult for a radar operator to discriminate between true target and false targets.